The court was ruling on a Ventura County case. The justices upheld the drug conviction of Gregory Diaz by a 5-2 vote.

Diaz was arrested for aiding in selling ecstasy to an informant during a sting operation. His cell phone was confiscated, along with six tabs of the drug.

Later, a detective who didn't have a search warrant found a text message on Diaz's phone about selling the drug. Diaz then admitted to participating in the deal and pleaded guilty to transporting a controlled substance. He was sentenced to probation, but reserved his right to appeal the use of his text message as evidence.

U.S. Supreme Court rulings have previously allowed warrantless searches of personal property such as clothing or cigarette packages that are "immediately associated" with the person who was arrested. Again in this case, they found that under the Fourth Amendment, law enforcement officers are permitted to search cell phones within the first 90 minutes following an arrest.

Justice Ming Chin, writing for the majority, said that Diaz's cell phone was similar to clothing, so it was able to be searched.

The ruling might help police find incriminating evidence, but it also raises privacy issues. Justice Kathryn Werdegar argued in dissent that searching someone's phone is "highly intrusive." She said that police should wait for a warrant and search the phone later.

Werdegar said developments in modern technology require the rulings to be reevaluated. But Chin said that any reevaluation "must be undertaken by the high court itself."